User-informed categorization of online content (e.g., web sites or email) is based on a model of express user feedback. If a user determines that a security product has blocked an appropriate web site, or has categorized a benign email message as spam, the user can expressly provide feedback to the product (or product's web site) to indicate that the site is not malicious or that the email message is not spam. For example, if the user wants access to a blocked site, the user typically expressly asks that the site be unblocked. In such case, a user can provide express feedback regarding the ultimate categorization of this site (e.g., that the site is not spam, or is for shopping, viewing sports, etc.).
One drawback to this “express feedback” approach is that it requires the user to make affirmative actions to provide the express user feedback. Another drawback is that it requires the user to actually view potentially offensive or inappropriate site before determining whether the site is appropriate. Often, users are unwilling to view a site because viewing of inappropriate sites may be tracked by the security product and reported to the user's employer in the form of a log.